compatibility problem in Questasim 6.4c

[raghava216]

Hi!

I wrote a controller design in vhdl and tested it with a script based test bench in Modelsim 6.0 SE.

When I run the test case 1, it got successfully executed and generated the required report files.
When the simulation is run in modelsim 6.0 SE for the first time ( irrespective of whether the previously created 'work' directory is deleted or not) It throws an error and simulation breaks with the message and reports are not getting generated.

# ** Failure: Simulation Finished
# Time: 51480 ns Iteration: 1 Process: /int_top/tb_top_i/mc_emulator_i/report_gen File: D:/projects/controller/code/tb/src/mc_emulator.vhd
# Break at D:/projects/controller/code/tb/src/mc_emulator.vhd line 787
# Simulation Breakpoint: Break at D:/projects/controller/code/tb/src/mc_emulator.vhd line 787
# MACRO D:\projects\controller\code\tb\sim\design.do PAUSED at line 299

Now, from second time onwards i.e. if I repeat the simulation in modelsim 6.0 SE by executing the macro again (irrespective of whether the previously created 'work' directory is deleted or not), It throws the following message. Reports are generated and no errors in the simulation process.

# ** Failure: Simulation Finished
# Time: 51480 ns Iteration: 1 Process: /int_top/tb_top_i/mc_emulator_i/report_gen File: D:/projects/controller/code/tb/src/mc_emulator.vhd
# Break at D:/projects/controller/code/tb/src/mc_emulator.vhd line 787
# tc_ctrl_01 Test Case Completed at Time : 51480000 ns

I am not able to trace the cause for this kind of behavior.

And in Questasim 6.4c,

when I run the test case 1, wherein a 'Z' value is read from a register, it gives a HREAD error and the displayed message is as follows:

# ** Error: (vsim-3855) HREAD Error: Read a ' z ', expected a Hex character (0-F).
# Time: 40240 ns Iteration: 1 Process: /int_top/tb_top_i/cmd_intr_i/interpretation File: D:/projects/controller/code/tb/src/cmd_intr.vhd
# Break in Process interpretation at D:/projects/controller/code/tb/src/cmd_intr.vhd line 268
# Simulation Breakpoint: Break in Process interpretation at D:/projects/controller/code/tb/src/cmd_intr.vhd line 268
# MACRO D:\projects\controller\code\tb\sim\design_run.do PAUSED at line 299

When the simulation is run from second time onwards, the behavior is same and it is unlike that in modelsim 6.0 SE, where it was successful.

With other test cases, which do not deal with 'Z' values, the message is as follows:

# Time: 51480 ns Iteration: 1 Process: /int_top/tb_top_i/mc_emulator_i/report_gen File: D:/projects/controller/code/tb/src/mc_emulator.vhd
# Break at D:/projects/controller/code/tb/src/mc_emulator.vhd line 787
# Simulation Breakpoint: Break at D:/projects/controller/code/tb/src/mc_emulator.vhd line 787
# MACRO D:\projects\controller\code\tb\sim\design.do PAUSED at line 299

This is the summary of the issues I am facing.

Looking fwd for solutions from experts in this area.